change colormap in Volume Viewer App

Is it possible to change the grayscale colormap to another colormap (e.g. jet) in Volume Viewer app?

Answer 1

[Walter Roberson]

volumeViewer is new in R2017a, and could use a number of improvements; I made a series of suggestions to Mathworks during pre-release. I did not, however, happen to think of asking about custom color maps.

The "Linear Grayscale" / "CT Bone" / "MRI" selector selects between three different colormaps. Unfortunately there is no option to choose other maps.

I suggest you create an enhancement request.

[Azadeh Sharafi]

Thanks for the answer. How can I make an enhancement request?

[Walter Roberson]

Create a support case with your suggestion.

[mengen Huang]

Is there a linear mapping between opacity and colormap ?I don't quite understand the functional relationship between the them. As we cam see in the picture the colors of 3D objects can't correspond to colormap？Looking forward to your reply.

[Walter Roberson]

The mapping is the blue plot to the right, the one that looks like a sideways Z. All of the values before a value near the mean have been assigned alpha 0, and so do not show up. The opacity increases over a short range. It happens that of the values that have been permitted to be visible, most of them are near the mean, and show up with the color that is underneath the step ascent on the Z, which is a green color. Some of the values are higher than that and show up in the color that is underneath their proportional value, in the yellow to early red range.

So:

1. colormap() your original data;
2. then set the alpha value according to the sideways-Z.

[mengen Huang]

Thank you for your reply. I'd like to know if there any way can I get the source code of the App? I want to know the internal logic of the App.I promise that it will not involve infringement. Looking forward to your reply. Thank you!

[Walter Roberson]

I'd like to know if there any way can I get the source code of the App?

Yes, the way to get source code to the App is to become a Mathworks employee or Mathworks Intern.

Or, as I like to remind people, a $US 5,000,000 non-refundable deposit gets you a meeting with Mathworks to discuss buying access to that source code.